Door latch assembly



y 1964 M. SALMUN 3,131,892

DOOR LATCH ASSEMBLY Filed June 11, 1962 2 Sheets-Sheet l INVENTOR. MO/SES .SALMUN A T TOP/V5 VS y 1964 M. SALMUN 3,131,892

DOOR LATCH ASSEMBLY Filed June 11, 1962 2 Sheets-Sheet 2 INVENTOR. MO/SES SAL MUN 2 -jww ATTORNEYS United States Patent 3,131,892 139GB LATCH ASSEMBLY Moises Salmun, Palo Alto, Calif., assignor, by mesne assignments, to The Eltra Corporation, Brooklyn, N.Y., a corporation of New York Filed lune 11, 1962, Ser. N 201,660 16 Claims. (ill. 244-129) This invention relates to a latch assembly for a closure member, and more particularly to a latch assembly for use with a closure door. The invention has particular utility in association with the closure doors of aircraft, such as helicopters.

In many environments it is necessary or desirable to have a closure member for an access opening that may be selectively secured not only in the completely closed and completely open positions thereof but also in a variety of intermediate position, and which closure member may be completely and easily removed or jettisoned when this is required. Aircraft, and particularly helicopters, are specific examples especially when used in military applications.

Although a variety of door latch and door jettisoning arrangements have been proposed, some of which are in use, such arrangements so far as is known are complex, cumbersome and heavy, or unreliable. Since these disadvantages are significant, an object of the present invention is to provide an improved door latch and door jettisoning assembly particularly suited for use with helicopters. Another object of the invention is that of providing for a slidable door, a latch assembly which is selectively movable among lock, release and jettison positions through a single control or actuator.

Still another object is in the provision of a latch assembly of the character described which may be selectively moved into any of such positions irrespective of the location of the door, and which permits the door to be fixedly located or locked in any desired position relative to the access opening associated therewith. Yet another object is to provide an assembly of the type described which automatically returns to the lock posifion thereof after being released to permit movement of the door, and which is equipped with stop means to prevent inadvertent jettisoning of the door.

A further object is that of providing a latch assembly for a slidable door that includes a track having a carrier assembly reciprocable therealong which supports the doorthe carrier assembly being adjustably related to the track to permit the ease of door movement to be selectively determined.

Still a further object is in the provision of a track and carrier assembly of the character described in which the carrier is elongated along the axis of reciprocation thereof so as to define a condition of stability for the door which tends to constrain the same against rotation in the plane thereof.

Yet a further object is to provide a latch assembly having an elongated track and a carrier reciprocable therealong, and in which the carrier may be locked in any selected position along the track by the development of frictional forces generally normal to such axis of reciprocation-the frictional forces being developed along opposite sides of the carrier and the respectively adjacent surfaces of the track by transverse displacements of the carrier, whereby compensation is afforded for any wearing of the frictionally engaging surfaces of the carrier and track by simply causing displacement of the carrier transversely to a greater extent when the latch assembly is in the locked position thereof.

A further object is that of providing a door and latch assembly of the type described which is simple, reliable, light-weight and which permits a jettisoned door to be "ice j replaced quickly and easily and without changing, altering or adjusting those components of the latch assembly which are carried by the aircraft body.

Additional objects and advantages will become apparout as the specification develops.

An embodiment of the invention is illustrated in the accompanying drawings in which FIG. 1 is a somewhat schematic side view in elevation of a helicopter embodying the invention;

FIG. 2 is a vertical sectional view taken along the plane 22 of FIG. 1;

FIG. 3 is a broken front view in elevation of the inner side of a door embodying the invention, portions of the inner door panel being broken away to show structural elements otherwise concealed thereby;

FIG. 4 is an exploded perspective view of certain components of the latch assembly;

FIG. 5 is an enlarged vertical sectional view taken along the plane 5-5 of FIG. 1;

FIG. 6 is an enlarged vertical sectional view taken along the plane 66 of FIG. 3;

FIGS. 7 and 8 are longitudinal sectional views taken generally along the length of the latch assembly as it is illustrated in FIG. 4 but with the components thereof assembled;

FIGS. 9 and 10 are top plan views of the components respectively illustrated in FIGS. 7 and 8; and

FIG. 11 is a top plan view similar to that of FIGS. 9 and 10, but showing the components in the jettison position thereof.

The invention is especially useful in association with a helicopter which may be substantially conventional, such as the helicopter 15 illustrated in FIGURE 1. Therefore, the helicopter has a body or fuselage 16, a rotary wing or main rotor assembly 17, a tail rotor assembly 18, and an undercarriage or landing skids 19. The fuselage 16 defines a compartment, access to which is provided through one or more openings 29 formed in the side walls or panels 21 of the fuselage. Each of the doorways or access openings 20 is adapted to be selectively covered by a closure member or door 22, which preferably conforms to the configuration of the wall 21 adjacent the opening 29. Thus, in the specific structure shown, the door 22 has a slight curvature or is somewhat arcuate from top to bottom since the fuselage panel 21 is so shaped.

The panel 21 is provided with an elongated slot or channel 23 that is horizontally disposed and extends generally along the upper edge portion of the opening 20 but in spaced relation therewith. As seen in FIGURE 1, the channel 23 projects substantially beyond the rear edge of the opening 29 when the door is in its closed position to permit the same to be displaced longitudinally along the fuselage to a fully open position. Secured to the panel 21 along the imer surface thereof by rivets or other suitable means is a longitudinally extending track defined by a generally box-shaped or hollow, rectangular channel 24 having a pair of oppositely oriented, laterally extending ears in engagement with the panel and through which such rivets extend. The vertically disposed walls 24a and 24b define a chamber 25 there'oetween. The wall 24b terminates at a location slightly below the center of the channel, and defines a groove or slot 25a that is in alignment with the lower edge portion of the slot 23 in the panel 21. The channel 24 is substantially coextensive in length with the slot 23, and is'disposed so that the slots 23 and 25a are in alignment from end to end thereof.

The panel 21 is equipped along the outer surface thereof with a generally L-shapedchannel 26 that is spaced slightly below the bottom edge of the opening 20 and is in substantially parallel alignment with the slot 23. The channel 26 is welded or otherwise rigidly secured to the panel 21, and one leg of the L extends downwardly along the panel in spaced relation therewith and defines a longitudinally elongated tongue adapted to be received Within a longitudinally disposed recess or groove 27 provided by'the door 22. The tongue 26 and groove 27 define a slidable engagement therebetween which permits the door 22 to be moved or displaced longitudinally along the length of the channel 26. Preferably, the groove 27 has an arcuate or gradual line of mergence with the inner surface of the door 22 so as to permit the door to drop downwardly to Withdraw the groove 27 from the tongue when the door is jettisoned, as will be described in detail hereinafter.

Constrained. for reciprocable movement within the track defined by the channel 24 is a carrier assembly 28 which is seen best in FIGURE 4. The assembly 28 is a tripartite component, the sections of which arerespectively designated with the numerals 29, 39 and 31. Each section is generally L-shaped and, therefore, the sections respectively have base legs 32, 33 and 34 and upright legs or stems 35, 36 and 37. In the particular carrier shown,

the assembly. 28 is segmented or divided into the three sections thereof, but a complete division of such character is not essential in that it is simply desired to have the center section 30 displaceable from front to rear, or generally normal to the longitudinal axis of the track, relative to the sections 2? and 31. It will be apparent that such relative movement of the sections could be achieved in some other manner as, for example, by having the sections 29 and 31 integral and the sectionSi) an insert slidably related to such integral sections. The reason for having the section Slidisplaceable with respect to the sections 29 and 31 will be brought out in detail hereinafter.

As shown in FIGURES 4 and 5, the upright legs 35, 36 and 37 are positioned Within the compartment 25 pro vided by the channel 24, and we longitudinally reciprocable along the length thereof. The base legs 32, 33 and 34 of the carrier assembly extend outwardly through the slots'25a and 23, and project beyond the outer surface of the panel 21. The base legs 32 and 34 terminate spaced distances inwardly from the respective outer ends of the sections 29 and 31, and are respectively provided with female threads or cam grooves 38 and 39 in the ends thereof which have a generally vertical disposition and extend from the top to the bottom of these base legs. The grooves SSand 39 are oppositely inclined, and (as shown most clearly in FIGURE the groove'ii extends upwardly and inwardly toward the plane of the panel 21, while the groove 39 extends upwardly and outwardly or away from the plane of the panel 21. The base leg 33 of the section 3% is provided with a cylindrical recess 40 in theouter face thereof.

Adapted to cooperatively engage the carrier assembly 28 is a nut or cam follower unit 41 having a generally 'U-shaped configuration defined by a base 42 and longitudinally spaced legs 43 and 44 which extend outwardly therefrom in substantially parallel relation. The distance between the inner surfaces of the legs 43 and 44 is slightly greater than the distance between the grooveequipped ends of the legs 32 and 34 of the carrier assembly when the various sections thereof are in adjacency, as shown in FIGURE 4. The legs 43 and 44 are respectively equipped with male threads or cam followers 45 and 46 which are adapted to be respectively received within the grooves 38 and 32. Thus, the threads 45 and 46 are generally vertically oriented, and have angular in-.

clinations which respectively correspond to those of the grooves 38 and 39. Therefore, and considering FIG- URES 5 and 6 which together illustrate the carrier assembly and earn follower unit .41 prior to the intercom nection thereof, the thread 45 extends upwardly and im wardly toward the plane of' the panel 21, and the thread 46 extends upwardly and outwardly with respect to the panel 21. f

' Welded or otherwise rigidly secured to the base 42 of the unit41 in a central location therealong is a cylindrical bearing 47' having a tapped passage extending is adapted to extend through the base 42 (as shown in FIGURE 4) so that its inner end can be received within the recess 49 of the carrier section 30. Preferably then, the inner end of the set screw'48is substantially cylindrical, and is so dimensioned so that it is rotatable with respect to the recess 40.

The bearing 47 is rotatably supported in a journal 49 provided by the door 22 in an ofliset portion of the inner panel or Wall 5% thereof. The outer wall 51 of the door is spaced from the inner panel 50, and a compartment 52 is defined therebetween. Formed integrally with the bearing 47 or otherwise rigidly related thereto is a de-' pending link 53 positioned Within the compartment 52 and oriented in generally parallel relation with the outer door panel 51. At its lower end, the link 53 is provided with an eyelet or opening that enables one end of a helical spring 54 to be connected thereto. The opposite end of the spring is connected to a lug 55 welded or otherwise securedto the inner surface of the outer door panel 51. Thus, as seen in FIGURE 3, the spring 54 biases the lower end portion of the link 53 toward the right, which tends to enforce a counterclockwise rotation uponthe bearing 47 and unit 41.

to the bifurcated end portion 56 of a rod 57, which at its opposite end is pivotally connected to an'elongated link 58 having an elongated slot in the upper end portion thereof which permits displacements between the rod 57 and link 58 as well as rotational movement therebe tween. At its lower end, the link 58 (which is disposed between the inner and outer door panels 59 and 51) has a pin 59 extending therethrough which also extends through the inner door panel 59 and through an operating handle 6% which is angularly disposed with respect to the link 58. Both the link 58 and handle 60 are rigidly secured to the pin 59 so that relative rotation therebetween is prevented; and the pin is rotatably supported by the door and defines the pivot axis for the members 58 and 60.

Pivotal movement of the handle 60 about the axis defined by the pin 59'is limited in a counterclockwise direction (as viewed in FIGURE 3) by a stop assembly'61 having an abutment 62 adapted to be engaged by the lower end of the handle. The stop assembly 61- issupported on a pin 63 for pivotal movement about the axis thereof, and is biased in a counterclockwise direction by a helical spring 64 which is secured to one end of the stop 61 and to the inner'panel 50 of the door. The abutment element 62 may be Withdrawn from the path of movement of the handle 60 by rotating the-stop 61 in a clockwise direction about the axis of the pin 63 against the biasing force of the spring 64. It will be apparent that the linkage composition and stop assembly described and illustrated is intended to be exemplary only of a of the longitudinally extending slot 23 formed in the fuselage panel 21 may serve as stop members that limit the reciprocable movement of the carrier assembly in opposite longitudinal directions, or the channel 24 or fuselage panel 21 may be equipped with separate stop elements that serve this function. Thus, the carrier assembly is constrained within the track for limited reciprocable movement generally along the longitudinal axis of the helicopter. l r

The cam follower unit 41 and various actuator components operatively associated therewith are suitably mounted in the door 22 so that the unit 41 is rotatable about the axis of the bearing 47 which is essentially coincident with the longitudinal axis of the set screw 48. The door may then be mounted upon the fuselage where it is supported by the cooperative engagement of the cam follower unit 41 with the carrier assembly 28. The requisite interconnection of the unit 41 with the assembly 28 is accomplished by rotating the unit 41 in a clockwise direction, as viewed in FIGURE 3, beyond the limit defined by engagement of the handle 60 with the abutment element 62. After such rotation of the unit 41, it will have the position relative to the assembly 28 which is illustrated in FIGURE 8.

The door 22 is then moved upwardly along the fuselage panel 21 to insert the depending tongue 26, which is disposed along the lower edge of the access opening 20, into the groove provided by the door 22 along the lower inner edge thereof. Thereafter, the upper end portion of the door may be moved into adjacency with the fuselage panel and, when the assembly 28 and unit 41 are in alignment, the end of the pin or set screw 48 will slip into the annular recess 49 of the central carrier section 30. Next, the unit 41 is rotated in a clockwise direction, as viewed in FIGURES 7 and 8 (counterclockwise as seen in FIGURE 3), which inserts the upper end of the male thread or cam follower 45 into the lower endof the female thread or cam slot 33, and the lower end of the thread 46 into the upper end of the cam slot 39. Continued rotation of the unit 41 in such direction fully inserts the threads 4%) and 45 into the respective slots 33 and 39, whereupon the assembly 28 and unit 41 are completely interengaged and the door 22 is then supported by the carrier assembly 28 through the cam folower unit 41.

When me unit 41 is in the generally horizontal position illustrated in FIGURES 3 and 9, the door 22 is constrained against reciprocable movement because of the frictional engagement of the outer surfaces of the carrier sections 29 and 31 with the inner surface of the channel wall 24b, as shown in FIGURE 9. At the same time, the inner surface of the central carrier section 30 is in frictional engagement with the inner surface of the channel wall 24a. Therefore, the total frictional force operative between the carrier assembly and channel which prevents movement of the door is the sum of the individual forces developed between the channel 24 and the respective ca rier sections 29, 30 and 31. It will be apparent that the magnitude of these constraining forces will depend upon the coefiicient of friction effective between the carrier assembly and channel surfaces and also upon the value of the transverse forces urging the respective carrier sections into engagement with the channel walls. Such transverse forces, in the particular embodiment disclosed, result from the helical spring 54 which releasably biases the unit 41 toward the lock position thereof.

Comparing FIGURES 9 and 10, which respectively represent the lock and release positions of the assembly, it is seen that the central section 30 of the carrier assembly is displaced inwardly with respect to the sections 29 and 31 when the door is locked. Such displacement occurs because of the relative movement, in directions generally normal to the longitudinal axis of the track, enforced on the assembly 28 and unit 41 as a consequence of the carnming function of the cam slots 38 and 39 and the respectively associated cam followers 45 and 46, whenever the unit 41 is rotated with respect to the assembly 28.

More particularly, and in further description of this function, rotation of the unit 41 in a clockwise direction, as viewed in FIGURES 7 and 8, causes the cam follower 45 to move upwardly through the cam slot 38 and, similarly, causes the cam follower 45 to move downwardly through the cam slot 39. In view of the angular inclinations of the slots 38 and 39 and corresponding inclinations of the cam followers 45 and 46, the assembly sections 2931 and the unit 41 are necessarily displaced relative to and toward each other. Thus, the cam slots and cam followers have the function of a coarse-pitch thread tending to advance the sections 29 and 31 (the bolt) into the unit 41 (the nut). As a result, the sections 29 and 31 are moved outwardly and into abutment with the channel wall 24b; and since the center section 30 of the assembly is in engagement with the unit 41 and cannot move outwardly with respect thereto, the center section 39 will be displaced toward and into abutment with the inner surface of the channel wall 24a, as shown in FIGURE 9. The more the unit 41 is rotated in the same direction, the tighter the abutment becomes between the respective carrier sections and the channel walls.

The initial position of the center section 39 with respect to the outer'sections 29 and 31 is selectively adjustable through the medium of the pin or screw 48. That is to say, if the screw is threaded farther into the tapped bore in the bearing 47, the center section 353 is necessarily dis placed toward the wall 24a of the channel and, conversely, if the screw is moved in the opposite direction, the center section 35 is free to move outwardly toward the wall24b of the channel. This arrangement permits the carrier assembly to be adjusted when necessary to compensate for any wear that may occur between the frictionally engaging surfaces of the carrier assembly and channel 24. Additionally, such adjustment determines the freedom or case with which the door 22 may be moved for any given position of the handle 69. The outer wall 51 of the door 22 may be provided with an opening and removable closure therefor through which the screw can be adjusted.

Quite apparently limited rotation of the unit 41 in the opposite direction from the position shown in FIGURE 9 and into the position illustrated in FIGURE 10 effects relative movement between the various sections of the carrier assembly and the unit 41 in the opposite directions, thereby releasing the carrier assembly from frictional engagement with the walls of the channel 24, which permits the door 22 to be reciprocated along the fuselage between its fully closed and fully opened positions. Rotational movement of the unit 41 in this direction is effected by displacing the handle 69 toward the abutment element 62. If the handle 60 is released, the spring 54 re turns the unit 41 to its locked position. Therefore, the door may be incrementally positioned between its fully opened and fully closed locations, and locked in any of such positions. 7

When it is desired to remove the door 22 as, for example, for jettisoning purposes, the handle 69 is displaced beyond the limit ordinarily defined by the abutment element 62, which is accomplished by rotating the stop lever 61 in a clockwise direction, as viewed in FIGURE 3, against the baising force of the spring 64 to remove the abutment element from the path of the handle. Such continued rotation causes the unit 41 to assume the position illustrated in FIGURE 8, in which the cam followers 45 and 46 are completely withdrawn from the respective cam slots 38 and 39. The door 22 is then free to fall downwardly and away from the fuselage since the only forces active on the door which tend to prevent such downward movement are imparted thereto through the cooperative interconnection of the assembly 28 and unit 41, which are now disengaged. As the door 22 drops downwardly, the groove 27 is withdrawn from the tongue 26 and the door is then completely free from the fuselage.

It is evident that the carrier assembly 28 is, in effect, a permanent or integral part of the helicopter, and that the unit 41 and associated actuating linkage is a permanent part of the door 22. Therefore, if a particular door is jettisoned in flight, another similar door may be mounted on the helicopter quickly and easily simply by inserting 7 the tongue 26 into the grOOVe 27 of such door and connecting the carrier assembly 28 and unit 41 in the manner heretofore described. The door 22 may be equipped with seals of suitable character so that a substantially airtight closure is provided about the opening 20, and it will be noted that the door 22 generally conforms-to the configuration of the adjacent fuselage panel 21 and is provided with an enlarged recess that receives the vunit 41 therein, whereby the inner panel 50 of the door is generally contiguous about the perimetric edge portions thereof with the fuselage panel 21.

While in the foregoing specification an embodiment of the invention has been set forth in considerable detail for purposes of making an adequatedisclosure thereof, it will be apparent to those skilled in the art that numerous changes maybe made in such details without departing from the spirit and principles of the invention.

Iclaim:

1. In combination with a wall panel having an opening therein and a closure panel therefor movable along said wall panel between open and closed locations, a car rier assembly supported by one of said panels, a unit supported by the other of said panels for cooperative associa tion with said carrier assembly, said carrier assembly be ing reciprocable along the path traversed by said closure panel in moving between such open and closedlocations thereof and having at least a section thereof transversely displaceable in one direction with respect to .such path to resist reciprocable movement of said carrier assembly, fastener structure having cooperative elements respectively provided by said carrier assembly and unit for releasably interconnecting the same to support said closure panel for such movement along said wall panel, said cooperative elements in the interconnected condition of said carrier assembly and unit being selectively mov able into a lock position displacing said section in such one transverse direction to resist reciprocation of said carrier assembly and thereby inhibit movement of said to a jettison position disconnecting said carrier assembly and unit for removal of said closure panel, and actuator structure for eflecting such relative movement of said cooperative elements into the lock, release and jettison positions thereof.

2. The combination of claim 1 in which said unit is rotatably supported by said closure panel, and in which said actuator structure is connected to said unit for selectively rotating the same to. effect the aforesaid relative movement of said cooperative elements into the lock, re lease and jettison positions thereof.

3. The combination of claim 2 in which saidcooperativeelements include male and female threads respectively associated with said carrier assembly and unit for selectively displacing saidsection toward and away from said unit upon limited rotational movement of the latter to establish the aforementioned lock and release positions. t V v 4. In combination with a panel having an opening therein and a closure therefor movable along said panel between open and closed locations, a track provided by said panel and extending along the path traversed by said closure in moving between such open and closed locations, a carrier assembly supported by said track for reciprocable movement therealong and having at least a section thereof transversely displaceable in one direction with respect to such path to resist reciprocable movement and unit selectively into a lock position displacing said section in such one transverse direction to resist reciprocation of said carrier assembly along said track and thereby inhibit movement of said closure, into a release position' in which said closure is movable between its open and closed locations, andinto a jettison position disconnecting said carrier assembly and unit for removal of said closure, and actuator structure for effecting such relative movement of said cooperative elements into the lock, release and jettison positions thereof.

5. In combination with a panel having an opening therein and a closure therefor movable along said panel between open and closed locations, a track provided by said panel and extending along the path traversed by said closure in moving between such open and closed locations, a carrier assembly supponted by said track for reciprocable movement the-realong and having 'at least a section thereof transversely displaceable in one direction with respect to such path to resist reciprocable movement of said carrier assembly, a unit carried by said closure for releasable interconnection with said carrier assembly to releasably support said closure thereon, fastener structure having cooperative elements respec tively provided by said carrier assembly and unitfor efiecting such releasable interconnection thereof, said cooperative elements including relatively rotatable male and female components respectively associated with said carrier assembly and unit for selectively displacing said section toward and away from said unit in such interconnected condition selectively into a lock position dis placing said section in such one transverse direction to resist reciprocation of said carrier assembly along said track and thereby inhibit movement of said closure, into a released position permitting reciprocablemovement of said carrier assembly along said track to move said closure between its open and closed locations, and into a jettison position disconnecting said carrier assembly and unit, and actuator structure for effecting relative rotation of said male and female components into the lock, release and jettison positions thereof.

' 6. The combination of claim 5 in which said male and female components comprise a female thread associated with said carrier assembly and a male thread associated with said unit.

7. The combination of claim 6 in which said female thread is discontinuous and defines a pair of threads re-' spectively disposed adjacent opposite end portions of said carrier assembly, and in which said male thread is also discontinuous and defines a pair of threads respectively disposed adjacent opposite end portions of said unit for engagement with the respectively corresponding female threads.

8. In combination with a helicopter having a fuselage defining a compartment therewithin and being equipped with a wall panel provided with an access opening for said compantment, a closure door longitudinally movable along said panel between open and closed positions, a

longitudinally extending track provided by said panel and having transversely spaced inner and outer walls, a carrier assembly supported by said track for reoiproca'ble movement therealong and being provided with a movable section transversely displaceable relative to said track walls, a unit rotaitably carried by said closure door for releasable interconnection with said cann'er assembly to releasably support said closure door thereby and being in engagement with said section to prevent transverse dis-' placement thereof in a direction toward said unit, fastener structure having cooperative elements respectively provided by said carrier assembly and unit and including relatively rotatable male and female components for selectively moving said carrier assembly and unit toward and away from each other upon limited rotational movements of said unitinthe interconnectedcondition thereof with said carrier assembly, relative rotation in one direction being effective to establish a lock position in which said carrier assembly is displaced transversely into abutment with the outer wall of said track with said section being transversely displaced into abutment with said inner wall so as to frictionmly constrain said carrier assembly against such reciprocable movement, relative rotation an opposite direction being efiective to establish a release position permitting reciprocable movement of said carrier assembly along said track to enable movement of said door between its open and closed positions, and further relative rotation in such opposite direction being effective to establish a jettison position in which said carrier assembly and unit are completely disconnected, and actuator structure connected with said unit for selec Lively rotating the same to efiect such relative movement of said elements into the lock, release and jettison positions thereof.

9. The combination of claim 8 in which said unit is equipped with an adjustable abutment eiining the aforesaid engagement of said unit with said section, said abutment being adjustable to determine the normal location of said section with respect to said track and thereby establish the ease of the reciprocatcry movement of said carrier along said track.

10. The combination of claim 8 in which resilient means are provided to bias said unit into the lock position thereof.

11. The combination of claim 8 in which releasable stop means are provided to limit movement of said actuator structure in a direction eiiecting complete release of said unit from said carrier assembly and thereby prevent inadvertent jettisoning of said closure door.

12. The combination of claim 8 in which said panel is equipped with a longitudinally extending depending tongue adjacent the lower edge of said access opening, and in which said closure door is provided with an upwardly facing, longitudinally extending recess receiving said tongue therein.

13. In a structure of the character described, a lon gitudinally extending track, a carrier assembly supported by said track for reciprocable movement therealong and comprising a pair of sections transversely displaceable with respect to said track and relative to each other between a release position in which said carrier assembly is reciprocable along said track and a lock position in which such movement is inhibited, and a control unit for cooperative association with said carrier assembly, said carrier assembly and control unit providing cooperative elements for releasably interconnecting the same, said elements in the interconnected condition of said carrier assembly and unit being movable selectively into a lock position displacing at least one of said sections transversely to inhibit reciprocable movement of said carrier assembly, into a released position in which said carrier assembly is reciprocable, and into a position disconnect ing said carrier assembly and unit, said cooperative elements including male and female threads respectively associated with said carrier assembly and unit and coperative with each other for establishing the aforementioned lock, release and disconnect positions, said female thread being discontinuous and defining a pair of threads respectively disposed adjacent opposite end portions of said carrier assembly, and in which said male thread is also discontinuous and defines a pair of threads respectively disposed adjacent opposite end portions of said unit for engagement with the respectively corresponding female threads.

14. In combination with a helicopter having a fuselage defining a compartment therewithin and being equipped with a wall panel provided with an access opening for said compartment, a closure door movable with respect to said panel between open and closed positions, a carrier assembly supported by said panel for movement relative thereto between positions respectively corresponding to such open and closed positions, a control unit pivotally supported by said closure door, fastener structure including cooperative elements respectively provided by said carrier assembly and unit for releasably interconnecting the same to support said closure door, said elements providing cooperative male and female threads for releasably interconnecting said carrier assembly and unit, and actuator structure connected with said unit for efiecting limited rotational movements thereof to selectively rotate said unit into a position in which said threads are engaged to support said closure door on said carrier as sembly and into a position in which said threads are dis engaged to completely release said unit and closure door from said carrier assembly and thereby efiect jettisoning of said closure door.

15. in combination with a helicopter having a fuselage defining a compartment therewithin and being equipped wi h a wall panel provided with an access opening for said compartment, a closure door longitudinally movable along said panel between open and closed positions, a longitudinally extend ng track provided by said panel, a carrier assembly supported by said track for reciprocable movement therealong and compris ng a pair of sections transversely displaceable with respect to said track and relative to each other between a release position in which said carrier assembly is reciprccable along said track and a lock position in which such movement is inhibited, and a control unit for cooperative association with said carrier assembly, said carrier assembly and control unit providing cooperative elements in the interconnected condition of said carrier assembly and unit being movable selectively into a lock position displacing at least one of said sections transversely to inhibit reciprocable movement of said carrier assembly, into a release position in which said carrier assembly is reciprocable, and into a position disconnecting said carrier assembly and unit, whereby said closure door is selectively constrainable against longitudinal movements, movable longitudinally between the open and closed positions thereof, and jettisonable from said helicopter.

16. In combination with a helicopter having a fuselage defining a compartment therewithin and being equipped with a wall panel provided with an access opening for said compartment, a closure door longitudinally movable along said panel between open and closed positions, a longitudinally extending track provided by said panel and having transversely spaced inner and outer walls, a carrier assembly supported by said track for reciprocable movement therealong and being provided with a movable section transversely displaceable relative to said track walls, a unit rotatably carried by said closure door for releasable interconnection with said carrier assembly to releasably support said closure door thereby, fastener structure having cooperative elements respectively provided by said carrier assembly and unit and including relatively rotatable male and female components for selectively moving said carrier assembly and unit toward and away from each other upon limited rotational movements of said unit, relative rotation in one direction being effective to establish a lock position in which said carrier assembly is displaced transversely into abutment with the outer wall of said track with said section being transversely displaced into abutment with said inner wall so as to frictionally constrain said carrier assembly against such reciprocable movement, and relative rotation in an opposite direction being eifective to establish a release position permitting reciprocable movement of said carrier assembly along said track to enable movement of said door between its open and closed positions.

References Cited in the file of this patent UNITED STATES PATENTS 782,139 Jones Feb. 7, 1905 2,445,131 Wartian July 13, 1948 3,020,604 Bransford Feb. 13, 1962 FOREIGN PATENTS 24,244 France Dec. 30, 1921 

14. IN COMBINATION WITH A HELICOPTER HAVING A FUSELAGE DEFINING A COMPARTMENT THEREWITHIN AND BEING EQUIPPED WITH A WALL PANEL PROVIDED WITH AN ACCESS OPENING FOR SAID COMPARTMENT, A CLOSURE DOOR MOVABLE WITH RESPECT TO SAID PANEL BETWEEN OPEN AND CLOSED POSITIONS, A CARRIER ASSEMBLY SUPPORTED BY SAID PANEL FOR MOVEMENT RELATIVE THERETO BETWEEN POSITIONS RESPECTIVELY CORRESPONDING TO SUCH OPEN AND CLOSED POSITIONS, A CONTROL UNIT PIVOTALLY SUPPORTED BY SAID CLOSURE DOOR, FASTENER STRUCTURE INCLUDING COOPERATIVE ELEMENTS RESPECTIVELY PROVIDED BY SAID CARRIER ASSEMBLY AND UNIT FOR RELEASABLY INTERCONNECTING THE SAME TO SUPPORT SAID CLOSURE DOOR, SAID ELEMENTS PROVIDING COOPERATIVE MALE AND FEMALE THREADS FOR RELEASABLY INTERCONNECTING SAID CARRIER ASSEMBLY AND UNIT, AND ACTUATOR STRUCTURE CONNECTED WITH SAID UNIT FOR EFFECTING LIMITED ROTATIONAL MOVEMENTS THEREOF TO SELECTIVELY ROTATE SAID UNIT INTO A POSITION IN WHICH SAID THREADS ARE ENGAGED TO SUPPORT SAID CLOSURE DOOR ON SAID CARRIER ASSEMBLY AND INTO A POSITION IN WHICH SAID THREADS ARE DISENGAGED TO COMPLETELY RELEASE SAID UNIT AND CLOSURE DOOR FROM SAID CARRIER ASSEMBLY AND THEREBY EFFECT JETTISONING OF SAID CLOSURE DOOR. 